[vnet_route_check] don't hardcode prefix length of /24

[stepanblyschak]

Signed-off-by: Stepan Blyschak [email protected]

What I did

Fix an issue when having /16 prefix on Vlan with vnet:

ERR vnet_route_check.py:  {'results': {'missed_in_app_db_routes': {'Vnet3': {'routes': ['172.3.255.254/32']}}}}

Interface     Master    IPv4 address/mask    Admin/Oper    BGP Neighbor     Neighbor IP
------------  --------  -------------------  ------------  ---------------  -------------
Loopback0               10.1.0.2/32          up/up         N/A              N/A
PortChannel1            10.100.0.16/31       up/up         TGS-SONIC-N2-S1  10.100.0.17
PortChannel2            10.100.0.18/31       up/up         TGS-SONIC-N2-S1  10.100.0.19
PortChannel3            10.100.0.20/31       up/up         TGS-SONIC-N2-S1  10.100.0.21
PortChannel4            10.100.0.22/31       up/up         TGS-SONIC-N2-S1  10.100.0.23
PortChannel5            10.100.0.24/31       up/up         PTR-SONIC-N2-S2  10.100.0.25
PortChannel6            10.100.0.26/31       up/up         PTR-SONIC-N2-S2  10.100.0.27
PortChannel7            10.100.0.28/31       up/up         PTR-SONIC-N2-S2  10.100.0.29
PortChannel8            10.100.0.30/31       up/up         PTR-SONIC-N2-S2  10.100.0.31
Vlan3         Vnet3     172.3.255.254/16     up/up         N/A              N/A
Vlan102                 22.144.1.254/16      up/up         N/A              N/A
docker0                 240.127.1.1/24       up/down       N/A              N/A
eth0                    10.144.253.130/16    up/up         N/A              N/A
lo                      127.0.0.1/8          up/up         N/A              N/A

How I did it

Avoid hardcoded /24 prefix.

How to verify it

Configure Vlan with /16 prefix and sudo vnet_route_check.py.

Previous command output (if the output of a command-line utility has changed)

New command output (if the output of a command-line utility has changed)

[prsunny]

lgtm, could you please raise a PR to 201911 separate

[stepanblyschak]

#1758